fusl/src/locale/newlocale.c

#include <stdlib.h>
#include <string.h>
#include "locale_impl.h"
#include "libc.h"

int __loc_is_allocated(locale_t loc) {
  return loc && loc != C_LOCALE && loc != UTF8_LOCALE;
}

locale_t __newlocale(int mask, const char* name, locale_t loc) {
  int i, j;
  struct __locale_struct tmp;
  const struct __locale_map* lm;

  /* For locales with allocated storage, modify in-place. */
  if (__loc_is_allocated(loc)) {
    for (i = 0; i < LC_ALL; i++)
      if (mask & (1 << i))
        loc->cat[i] = __get_locale(i, name);
    return loc;
  }

  /* Otherwise, build a temporary locale object, which will only
   * be instantiated in allocated storage if it does not match
   * one of the built-in static locales. This makes the common
   * usage case for newlocale, getting a C locale with predictable
   * behavior, very fast, and more importantly, fail-safe. */
  for (j = i = 0; i < LC_ALL; i++) {
    if (loc && !(mask & (1 << i)))
      lm = loc->cat[i];
    else
      lm = __get_locale(i, mask & (1 << i) ? name : "");
    if (lm)
      j++;
    tmp.cat[i] = lm;
  }

  if (!j)
    return C_LOCALE;
  if (j == 1 && tmp.cat[LC_CTYPE] == &__c_dot_utf8)
    return UTF8_LOCALE;

  if ((loc = malloc(sizeof *loc)))
    *loc = tmp;

  return loc;
}

weak_alias(__newlocale, newlocale);